Organic el display device

ABSTRACT

An organic EL display device according to an embodiment of the present invention includes: a substrate, a plurality of pixels that are disposed on the substrate, a first inorganic insulating layer that covers the plurality of pixels, a conductive layer that is disposed on a side of the first inorganic insulating layer opposite to the plurality of pixels and covers the plurality of pixels, and a second inorganic insulating layer that is disposed on a side of the conductive layer opposite to the first inorganic insulating layer and covers the plurality of pixels.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 35 U.S.C. 120 of InternationalApplication PCT/JP2018/001951 having the International Filing Date ofJan. 23, 2018, and having the benefit of the earlier filing date ofJapanese Application No. 2017-078826, filed on Apr. 12, 2017. Each ofthe identified applications is fully incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

One or more embodiments of the present invention relate to an organic ELdisplay device.

2. Description of the Related Art

An organic electroluminescence (EL) display device has a display panelwhere a thin film transistor (TFT), an organic light emitting diode(OLED), and the like are formed on a substrate. A display panel likethis generates electromagnetic noise, and may trigger, for example, amalfunction of an attached touch panel. With respect to such a problem,for example, in Japanese Patent Application Laid-Open No. 2003-099193,it is suggested to form an ITO film on a substrate of a touch panel partand a substrate of a display panel part.

SUMMARY OF THE INVENTION

However, adverse effects of the electromagnetic noise are expected to bemore reliably suppressed.

One or more embodiments of the invention have been made in view of theabove, and it is an object thereof to provide an organic EL displaydevice that can more reliably suppress adverse effects of theelectromagnetic noise.

An organic EL display device according to an embodiment of the presentinvention includes: a substrate, a plurality of pixels that are disposedon the substrate, a first inorganic insulating layer that covers theplurality of pixels, a conductive layer that is disposed on a side ofthe first inorganic insulating layer opposite to the plurality of pixelsand covers the plurality of pixels, and a second inorganic insulatinglayer that is disposed on a side of the conductive layer opposite to thefirst inorganic insulating layer and covers the plurality of pixels.

In one embodiment of the present invention, a touch panel is positionedon a side of the second inorganic insulating layer opposite to theconductive layer.

In one embodiment of the present invention, sheet resistance of theconductive layer is 500Ω per square or less.

In one embodiment of the present invention, the conductive layer has avisible light transmittance of 50% or more.

In one embodiment of the present invention, the conductive layerincludes a binder resin.

In one embodiment of the present invention, the conductive layerincludes a nanowire and/or a nanotube.

In one embodiment of the present invention, the conductive layerincludes an ITO.

In one embodiment of the present invention, the conductive layerincludes a resin and a conductive material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a schematic configuration of an organic ELdisplay device according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of an example of a display panel of theorganic EL display device illustrated in FIG. 1.

FIG. 3 is a view of an example of cross section of FIG. 2.

FIG. 4 is a schematic cross sectional view of an example of a statewhere a touch panel is placed on the display panel illustrated in FIG.2.

DETAILED DESCRIPTION OF THE INVENTION

Below, the respective embodiments of the present invention are explainedwith reference to the accompanying drawings. Note that the disclosedembodiments are merely examples, and an appropriate variation which aperson skilled in the art can easily arrive at without departing fromthe spirit of the present invention is naturally included in the scopeof the present invention. Further, while the width, thickness, shape,and the like of each part in the drawings may be illustratedschematically as compared with the actual embodiments in order toclarify the explanation, these are merely examples, and aninterpretation of the present invention should not be limited thereto.Furthermore, in the specification and the respective drawings, the samereference symbols may be applied to elements similar to those which havealready been illustrated in another drawing, and a detailed explanationof such elements may be omitted as appropriate.

FIG. 1 is a schematic view of a schematic configuration of an organic ELdisplay device according to an embodiment of the present invention. Anorganic EL display device 2 is provided with a pixel array part 4 whichdisplays an image, and a driving part which drives the pixel array part4. The organic EL display device 2 has a display panel where alamination structure of a TFT, an OLED, and the like is formed on asubstrate. Note that the schematic view illustrated in FIG. 1 is anexample, and the present embodiment is not limited thereto.

On the pixel array part 4, OLEDs 6 and pixel circuits 8 are arranged ina matrix form, in correspondence with the respective pixels. The pixelcircuit 8 is composed of a plurality of TFTs 10 and 12, and a capacitor14.

The driving part as described above includes a scan line driving circuit20, an image line driving circuit 22, the driving power source circuit24, and the control device 26, and drives the pixel circuit 8 to controllight emission of the OLED 6.

The scan line driving circuit 20 is connected to a scan signal line 28provided for each horizontal line of pixels (pixel row). The scan linedriving circuit 20 selects scan signal lines 28 in order according totiming signals input from the control device 26, and applies an electricvoltage for turning on the lighting TFT 10 to the selected scan signalline 28.

The image line driving circuit 22 is connected to an image signal line30 provided for each vertical line of pixels (pixel column). The imageline driving circuit 22 receives an input of an image signal from thecontrol device 26, and in accordance with a selection of the scan signalline 28 by the scan line driving circuit 20, outputs an electric voltageaccording to the image signal for the selected pixel row to each imagesignal line 30. That electric voltage is written into the capacitor 14via the lighting TFT 10 at the selected pixel row. The driving TFT 12supplies the OLED 6 with an electric current according to the writtenelectric voltage, and thus the OLED 6 of the pixel which corresponds tothe selected scan signal line 28 emits light.

The driving power source circuit 24 is connected to a driving electricpower supply line 32 provided for each pixel column, and supplies theOLED 6 with an electric current via the driving electric power supplyline 32 and the driving TFT 12 in the selected pixel row.

Here, a lower electrode of the OLED 6 is connected to the driving TFT12. Whereas, an upper electrode of each OLED 6 is composed of anelectrode shared in common by the OLEDs 6 of all the pixels. In a casewhere the lower electrode is configured as an anode, a high electricpotential is input thereto, and the upper electrode becomes a cathodeand a low electric potential is input thereto. In a case where the lowerelectrode is configured as a cathode, a low electric potential is inputthereto, and the upper electrode becomes an anode and a high electricpotential is input thereto.

FIG. 2 is a schematic plan view of an example of the display panel ofthe organic display device illustrated in FIG. 1. The pixel array part 4illustrated in FIG. 1 is provided in a display area 42 of the displaypanel 40, and as described above the OLEDs are arranged on the pixelarray part 4. As described above, an upper electrode 44 whichconstitutes the OLED 6 is formed so as to be shared in common by therespective pixels and covers the entire display area 42.

On one side of the display panel 40 which has a rectangular shape, acomponent mounting area 46 is provided, and a wiring connected to thedisplay area 42 is disposed thereon. Further, on the component mountingarea 46 a driver integrated circuit (IC) 48 which constitutes thedriving part is mounted, and an FPC 50 is connected to the componentmounting area 46. The flexible printed circuit (FPC) 50 is connected tothe control device 26, and other circuits 20, 22, and 24, and the like,and an IC is mounted on the FPC 50.

FIG. 3 is a view of an example of cross section of FIG. 2. The displaypanel 40 has a structure where a circuit layer composed of a TFT 72 andthe like, the OLED 6, a sealing layer 106 which seals the OLED 6, andthe like are laminated on a substrate 70. The substrate 70 is composedof, for example, a glass board, or a resin film such as polyimide resin.In the present embodiment, the pixel array part 4 is a top emission typepixel array, and light generated in the OLED 6 is emitted to a sideopposite from the substrate 70 side (in an upper direction in FIG. 3)with respect to the OLED 6. In a case where a colorization method of theorganic EL display device 2 is set to the color filter method, the colorfilter is arranged over the sealing layer 106, for example. By lettingwhite light generated in the OLED 6 go through this color filter, lightsin colors such as red (R), green (G), and blue (B) are generated, forexample.

On the circuit layer of the display area 42, the pixel circuit 8, thescan signal line 28, the image signal line 30, and the driving electricpower supply line 32 which have been described above, and the like areformed. At least a part of the driving part can be formed as a circuitlayer in an area adjacent to the display area 42, on the insulating basematerial 70. As described above, the driver IC 48 and the FPC whichconstitute the driving part can be connected to a wiring 116 of thecircuit layer in the component mounting area 46.

As illustrated in FIG. 3, on the substrate 70, an under-layer 80 whichis formed of an inorganic insulating material is arranged. As theinorganic insulating material, for example, silicon nitride (SiN_(y)),silicon oxide (SiO_(x)), or a complex of these is used.

In the display area 42, with an interposition of the under-layer 80, asemiconductor area 82 to be a channel part and the source/drain part ofthe top gate type TFT 72 is formed on the substrate 70. Thesemiconductor area 82 is formed of, for example, polysilicon (p-Si). Thesemiconductor area 82 is formed by, for example, providing asemiconductor layer (a p-Si film) on the substrate 70, patterning thissemiconductor layer, and selectively leaving parts which are used in thecircuit layer. Over the channel part of the TFT 72, a gate electrode 86is arranged with an interposition of a gate insulating film 84. The gateinsulating film 84 is typically formed of TEOS. The gate electrode 86 isformed by, for example, patterning a metal film formed by sputtering orthe like. On the gate electrode 86, an interlayer insulating layer 88 isarranged so as to cover the gate electrode 86. The interlayer insulatinglayer 88 is formed of, for example, the inorganic insulating material asdescribed above. In the semiconductor area 82 (p-Si) to be thesource/drain part of the TFT 72, impurities are introduced by an ioninjection, and further a source electrode 90 a and a drain electrode 90b which are electrically connected thereto are formed, and thus the TFT72 is formed.

On the TFT 72, an interlayer insulating film 92 is arranged. On thesurface of the interlayer insulating film 92, a wiring 94 is arranged.The wiring 94 is formed by, for example, patterning a metal film formedby sputtering or the like. With a metal film which constitutes thewiring 94, and a metal film which is used to form the gate electrode 86,the source electrode 90 a and the drain electrode 90 b, for example, thewiring 116, and the scan signal line 28, the image signal line 30, andthe driving power supply line 32 which are illustrated in FIG. 1 can beformed as a multilayer wiring structure. Thereon, a planarizing film 96is formed, for example, of a resin material such as an acrylic resin,and in the display area 42, the OLED 6 is formed on the planarizing film96.

The OLED 6 includes a lower electrode 100, an organic material layer102, and an upper electrode 104. The organic material layer 102includes, specifically, a hole transport layer, a light emitting layer,an electron transport layer, and the like. The OLED 6 is typicallyformed by laminating the lower electrode 100, the organic material layer102, and the upper electrode 104 in this order from the substrate 70side. In the present embodiment, the lower electrode 100 is an anode ofthe OLED, and the upper electrode 104 is a cathode.

If the TFT 72 illustrated in FIG. 3 is the driving TFT 12 having ann-channel, the lower electrode 100 is connected to the source electrode90 a of the TFT 72. Specifically, after forming the planarizing film 96as described above, a contact hole 110 for connecting the lowerelectrode 100 to the TFT 72 is formed, and for example by patterning aconductive body part formed on the surface of the planarizing layer 96and inside the contact hole 110, the lower electrode 100 connected tothe TFT 72 is formed for each pixel.

On the structure as described above, a bank 112 which separates pixelsis arranged. For example, after forming the lower electrode 100, thebank 112 is formed on a border of pixels, and in an effective area of apixel surrounded by the bank 112 (an area where the lower electrode 100is exposed), the organic material layer 102 and the upper electrode 104are laminated. The upper electrode 104 is typically formed of atransparent electrode material.

On the upper electrode 104, a sealing layer 106 is arranged. The sealinglayer 106 can function as, for example, a protection layer whichprotects the OLED 6 from moisture and the like, and therefore thesealing layer 106 is formed to cover the whole of the display area 42.Although not shown here, a protection layer can be disposed on thedisplay area 42 so as to ensure mechanical strength of the surface ofthe display panel 40, for example. In this case, a protection layer isnot typically provided on the component mounting area 46 so as tofacilitate connection of the IC and the FPC to the component mountingarea 46. A wiring of the FPC 50 and a terminal of the driver IC 48 areelectrically connected to, for example, the wiring 116.

As a method of installing a touch panel on the display device, aconfiguration of externally attaching the touch panel to the displaypanel (out-cell method), a configuration of providing the touch paneloutside the display panel (for example, between the display panel andthe polarizing plate arranged outside the display panel) and integratingthe display panel and the touch panel (on-cell method), and aconfiguration of providing the touch panel inside the display panel(in-cell method) are known. In the present embodiment, the out-cellmethod or the on-cell method are adopted. Specifically, as illustratedin FIG. 4, the touch panel 60 is arranged on the sealing layer 106 ofthe display panel 40, and in this state, the display panel 40 is putinside a housing of the organic EL display device 2. Note that in FIG.4, as the lamination structure of the display panel 40 illustrated inFIG. 3, a lamination structure from which the sealing layer 106 over thesubstrate 70 is omitted is illustrated as an upper structure layer 114,in a simplified manner.

The sealing layer 106 includes a first sealing layer 106 a, a conductivelayer 108, and a second sealing layer 106 b in this order from thesubstrate 70 side. As shown, the conductive layer 108 is not provided onthe edge of the sealing layer 106 outside the display area 42, and thefirst sealing layer 106 a is in direct contact with the second sealinglayer 106 b. The sealing layer 106 includes the conductive layer in thismanner, thereby shielding the electromagnetic noise at a position closerto the sources of the noise (display part). This can suppress theadverse effects of electromagnetic noise more reliably. For example, itis possible to more reliably suppress a malfunction of a touch panel.Further, a conductive layer can be formed in the step of forming asealing layer, and this serves to improve manufacturing efficiency.

The first sealing layer (inorganic insulating layer) 106 a and thesecond sealing layer (inorganic insulating layer) 106 b are each formedby, for example, forming a film of inorganic insulating material, suchas SiN_(y), to have a thickness of several μm or so using a chemicalvapor deposition (CVD) method. By inserting the conductive layer 108between such sealing layers, in other words, covering the entireconductive layer 108 with the first sealing layer 106 a and the secondsealing layer 106 b, adverse effects of the conductive layer 108 on theother members can be suppressed. The conductive layer 108 is formed soas to cover the display area 42. The conductive layer 108 is preferablyformed such that the sheet resistance is 500Ω per square or less inorder to achieve, for example, satisfactory effects of shieldingelectromagnetic noise generated on the display part (the structure layer114 below the sealing layer 106). Further, the conductive layer 108 ispreferably formed so as to ensure transparency (e.g., having a visiblelight transmittance of 50% or more).

The conductive layer 108 includes conductive material. For example,following materials are used as the conductive material: metals such assilver, gold, copper, nickel, and alloys of these metals (e.g., Cu—Ni);carbon; metal oxide such as indium tin oxide (ITO); andelectroconductive polymer.

The conductive layer 108 includes, for example, a binder resin such asan acrylic resin and the conductive material described above. In thiscase, the thickness of the conductive layer 108 is 10 μm to 50 μm, forexample. The conductive material used in combination with the binderresin may be formed appropriately, although a nanowire (typically, metalnanowire) and/or a nanotube (typically, carbon nanotube) are preferablyused. The metal nanowire is particularly preferred between them. Themetal nanowire can satisfactorily achieve, for example, the conductivityand transparency described above. Here, the nanowire is a fiber-likeconductive substance with a solid structure having a diameter ofnanometer size, and the nanotube is a fiber-like conductive substancewith a hollow structure having a diameter of nanometer size. Thicknessesof the nanowire and the nanotube are, for example, 5 nm to 500 nm, andare preferably 5 nm to nm. Lengths of the nanowire and the nanotube are,for example, 1 μm to 1000 μm, and are preferably 10 μm to 1000 μm. Theconductive layer 108 is formed by, for example, applying an applicationmaterial containing the binder resin and the conductive material to thefirst sealing layer 106 a (e.g., by using the inkjet method), andsubjecting the application material to a post-treatment (e.g., heatcuring treatment and light curing treatment) as appropriate according toa type of the binder resin. The conductive layer 108 can also functionas a flattening layer of the sealing layer 106.

The present invention is not limited to the embodiments as have beendescribed above, and various kinds of variations are acceptable. Forexample, the configurations explained as to the above embodiments can bereplaced with a configuration which is substantially the same as theones which have been explained regarding the embodiments describedabove, a configuration which exhibits the same technical effect, or aconfiguration which can achieve the same objective. Specifically, theconductive layer 108 may be formed of an ITO film, for example.

It is understood that without departing from the spirit of the presentinvention, those skilled in the art can arrive at various kinds ofvariations and modifications, and such variations and modificationsbelong to the scope of the present invention. For example, each of theembodiments as described above to which addition, deletion, or designchange of components, or addition, omission, or condition change ofprocesses is suitably applied by those skilled in the art are alsoencompassed within the scope of the present invention as long as theyfall within the spirit of the present invention.

What is claimed is:
 1. An organic EL display device, comprising: asubstrate, a plurality of pixels that are disposed on the substrate, afirst inorganic insulating layer that covers the plurality of pixels, aconductive layer that is disposed on a side of the first inorganicinsulating layer opposite to the plurality of pixels and covers theplurality of pixels, and a second inorganic insulating layer that isdisposed on a side of the conductive layer opposite to the firstinorganic insulating layer and covers the plurality of pixels.
 2. Theorganic EL display device according to claim 1, wherein a display areaincluding the plurality of pixels is positioned on the substrate, thefirst inorganic insulating layer, the conductive layer, and the secondinorganic insulating layer cover the display area, a part of the firstinorganic insulating layer is positioned on outside of the display area,a part of the second inorganic insulating layer is positioned on theoutside, and an edge of the first inorganic insulating layer overlaps anedge of the second inorganic insulating layer in a plan view on theoutside.
 3. The organic EL display device according to claim 2, whereina part of the conductive layer is positioned on the outside, and an edgeof the part of the conductive layer is positioned between the edge ofthe first inorganic insulating layer and the display area.
 4. Theorganic EL display device according to claim 1, wherein the firstinorganic insulating layer includes an area that is in direct contactwith the second inorganic insulating layer, and all of the conductivelayer is covered by the first inorganic insulating layer and the secondinorganic insulating layer.
 5. The organic EL display device accordingto claim 1, wherein each of the plurality of pixels includes a lowerelectrode, a light emitting layer on the lower electrode, and an upperelectrode on the light emitting layer, the first inorganic insulatinglayer is positioned on the upper electrode, and the first inorganicinsulating layer and the second inorganic insulating layer are sealinglayers that seal the light emitting layer.
 6. The organic EL displaydevice according to claim 1, wherein a touch panel is positioned on aside of the second inorganic insulating layer opposite to the conductivelayer.
 7. The organic EL display device according to claim 1, whereinthe conductive layer includes a binder resin.
 8. The organic EL displaydevice according to claim 1, wherein the conductive layer includes ananowire and/or a nanotube.
 9. The organic EL display device accordingto claim 1, wherein the conductive layer includes an ITO.
 10. Theorganic EL display device according to claim 1, wherein the conductivelayer includes a resin and a conductive material.
 11. The organic ELdisplay device according to claim 1, wherein sheet resistance of theconductive layer is 500Ω per square or less.
 12. The organic EL displaydevice according to claim 1, wherein the conductive layer has a visiblelight transmittance of 50% or more.
 13. An organic EL display devicecomprising: a plurality of pixels each including a lower electrode, alight emitting layer on the lower electrode, and an upper electrode onthe light emitting layer, a first sealing layer that is positioned onthe upper electrode and covers the plurality of pixels, a conductivelayer that is positioned on a side of the first sealing layer oppositeto the plurality of pixels and covers the plurality of pixels, a secondsealing layer that is positioned on a side of the conductive layeropposite to the first sealing layer and covers the plurality of pixels,and a touch panel that is positioned on a side of the second sealinglayer opposite to the conductive layer.
 14. The organic EL displaydevice according to claim 13, wherein the first sealing layer includesan area that is in direct contact with the second sealing layer, and allof the conductive layer is covered by the first sealing layer and thesecond sealing layer.
 15. The organic EL display device according toclaim 13, wherein the first sealing layer, the conductive layer, and thesecond sealing layer are provided across the display area and outside ofthe display area, the display area including the plurality of pixels,and an edge of the first sealing layer overlaps an edge of the secondsealing layer in a plan view on the outside.
 16. The organic EL displaydevice according to claim 15, wherein an edge of the conductive layer onthe outside is positioned between the edge of the first sealing layerand the display area.
 17. The organic EL display device according toclaim 13, wherein the conductive layer includes a binder resin.
 18. Theorganic EL display device according to claim 13, wherein the conductivelayer includes a nanowire and/or a nanotube.